1. Field of the Invention
The present invention relates to a vertically telescopic robot and, more particularly to a robot suitable for operation in a clean room.
2. Description of the Related Art
Conventionally, in manufacturing equipment installed in a clean room, such as semiconductor wafer manufacturing equipment, when a large stroke of vertical movement is required, a cylindrical coordinates robot a shown in FIGS. 1, 2 is used for handling a work w such as a semiconductor wafer.
As shown in FIG. 1, to rotate and convey the work w in a horizontal plane in xcex8 direction around Z-axis, the cylindrical coordinates robot a is structured such that a column-shaped Z-axis member e is provided upwardly from an upper face d of a rotating member c pivotally mounted on a base unit b, and a horizontal member f having a wafer handling unit g is mounted on the Z-axis member e such that it is vertically movable. The wafer handling unit g is mounted such that it can reciprocate in X-axis direction (horizontal direction) in FIG. 1. According to the configuration of the cylindrical coordinates robot a, the horizontal member f moves up/down between a lower end position shown in FIG. 1 and an upper end position shown in FIG. 2, and the Z-axis member e, together with the rotating member c, rotates in the xcex8 direction around the Z-axis. Thereby, the wafer handling unit g conveys the work w such as the semiconductor wafer to a predetermined position.
In some cases, in the manufacturing equipment, instead of the cylindrical coordinates robot a shown in FIGS. 1, 2, an articulated robot h shown in FIGS. 3, 4, as a general industrial robot is used. The articulated robot h is configured such that a wafer handling unit k is attached to a tip end of an arm j having a base end attached to a rotatable base unit i. The arm j has a plurality of joints m1, m2, m3 and is bendable. According to the configuration of the articulated robot h, the wafer handling unit k is displacable in Z-axis direction between an upper position shown in FIG. 3 and a lower position shown in FIG. 4 and is movable in a horizontal plane. Also, the arm j is displacable in xcex8 direction around the Z-axis.
However, in the articulated robot h, if the arm j is bent by a large angle to reduce a length thereof in the Z-axis direction as shown in FIG. 4, that is, to lower the wafer handling unit k, a portion such as the joint m2, is greatly protruded from the base unit i in horizontal direction X and tends to interfere with its vicinity. For this reason, it is difficult to make the entire device using the articulated robot h compact.
In a clean room or a clean booth of which extremely high level cleanliness is demanded, air purifying equipment costs a great deal, and it is therefore necessary to minimize a foot print (foot area) of the manufacturing equipment in order to reduce a cost per unit area. Accordingly, most of respective devices in the manufacturing equipment are vertically provided, and the operation in the Z-axis direction of the robot for use in the manufacturing equipment is necessarily increased. Under the circumstance, the cylindrical coordinates robot a shown in FIGS. 1, 2, which does not significantly interfere with its vicinity and has a long stroke in the vertical direction, has been mainly used.
However, in the cylindrical coordinates robot a shown in FIGS. 1, 2, because a space for the Z-axis member e is required beside a space for the wafer handling unit g for conveying the work w in the Z-axis direction, an interferential space n is formed, as shown in a plan view of FIG. 5. This interferential space n impedes the device using the cylindrical coordinates robot a from being made compact, although it is smaller than an interferential space of the articulated robot h shown in FIGS. 3, 4.
When horizontally handling a disc-shaped work w such as the semiconductor wafer or a glass electrode for liquid crystal, there is a possibility that dust is generated from an upper portion of the Z-axis member e that is situated above the work w and falls on a surface of the work w and the work w is contaminated. For this reason, it is sometimes difficult to keep the demanded cleanliness of the work w.
Since the Z-axis member e have a length greater than that of a displacement stroke in the Z-axis direction of the wafer handling unit g of the horizontal member f, the member e is difficult to handle in installation or maintenance. For example, when carried into/out of the clean room, the long Z-axis member e must be handled as it is, which makes operation difficult. Also, when transferred from a manufacturing factory to a place where the member e is used, the Z-axis member e tends to be damaged and is bulky during transfer is reduced, because the long Z-axis member must be handled as it is.
By the way, as a horizontal movement mechanism of the wafer handling unit g, prior arts using a multistage slide mechanism, with higher space efficiency, are disclosed in Japanese Laid-Open Patent Publication No. Sho. 58-84435 (1983), Japanese Laid-Open Patent Publication No. Sho. 62-297085 (1987), Japanese Laid-Open Patent Publication No. Hei. 9-36200 (1997), and the like.
In these prior arts, up-down axes are moved in a horizontal direction. As a matter of course, these axes can be applied to vertical movement. However, since sliders in the respective stages are driven by combination of a rope and pulleys, it is not easy for the multistage slide mechanism to withstand excess weight including its own weight. When a highly rigid metal wire is used as the rope as a solution to the above problem, another problem that a holding force of the sliders is reduced because friction generated between the wire and the pulleys is small, will arise. Consequently, the configuration disclosed in each of the Publications, without being altered, cannot be applied to the cylindrical coordinates robot a.
Japanese Laid-Open Patent Publication No. Hei. 11-87461 (1999) discloses a substrate conveying device that holds a substrate and conveys the substrate to a predetermined position, comprising: a sweepable conveying arm that holds the substrate and conveys the substrate in the horizontal direction; a telescopic up-down mechanism that extends/retracts in the vertical direction to move the conveying arm up/down; and a cover provided such that it covers the telescopic up-down mechanism, extending/retracting in association with extension/retraction of the telescopic up-down mechanism, and having an opening in an upper face thereof.
However, in the device disclosed in the Japanese Laid-Open Patent Publication No. Hei. 11-87461 (1999), since the cover of the telescopic up-down mechanism is separated from the telescopic up-down mechanism, a foot print cannot be made sufficiently small. In addition, since this large cover, together with the telescopic up-down mechanism, extends/retracts during the extension/retraction of the telescopic up-down mechanism, air flow is greatly disordered, which tends to cause powder dust to swirl.
The present invention has been developed for obviating the above-described problems and an object of the present invention is to provide a robot comprising a telescopic-drive mechanism which does not contaminate works in a purified environment such as a clean room, is easy to handle, and requires no cover for covering the telescopic-drive mechanism.
According to an embodiment of the present invention, there is provided a robot comprising: an up-down axis in which a plurality of hollow axis sectional elements telescopically continue; and a telescopic-drive mechanism for driving the up-down axis to be vertically extended or retracted between an extended state in which a tip end of the up-down axis extends with respect to a base end thereof and a retracted state in which the tip end is moved close to the base end, wherein the telescopic-drive mechanism is integrated on one side of the up-down axis without being exposed from the up-down axis.
According to another embodiment of the present invention, there is provided a robot comprising: an up-down axis in which a plurality of hollow axis sectional elements telescopically continue; a telescopic-drive mechanism for driving the up-down axis to be vertically extended or retracted between an extended state in which a tip end of the up-down axis extends with respect to a base end thereof and a retracted state in which the tip end is moved close to the base end; and an operation axis unit having a rotatable base provided at a top portion of the up-down axis, wherein the telescopic-drive mechanism is integrated on one side of the up-down axis without being exposed from the up-down axis.
It is preferable that the robot comprises an exhaust means provided at a lower end portion of the up-down axis, for exhausting a gas inside of the up-down axis, or an exhaust duct provided at the lower end portion of the up-down axis such that the exhaust duct communicates with the interior of the up-down axis, thereby making an interior of the up-down axis have a negative pressure.
In the robot of the present invention, the telescopic-drive mechanism is structured such that the up-down axis comprises: a main up-down means for moving a second axis sectional element up or down with respect to a first axis sectional element situated at the base end, the second axis sectional element being situated above the first axis sectional element; and a subordinate up-down means for moving remaining axis sectional elements other than the second axis sectional element up or down, following up movement or down movement of the second axis sectional element. In this case, it is preferable that the up-down axis has a substantially rectangular cross section and the main up-down means and the subordinate up-down means are provided on a side face of a long side of the rectangular cross section of the up-down axis.
It is preferable that the main up-down means comprises a ball screwing mechanism. The subordinate up-down means comprises: a band-shaped or line-shaped drive member having flexibility; and a rotating member, and the rotating member is rotatably mounted to an upper end portion of a storage portion of an intermediate axis sectional element, the drive member is installed around the rotating member, and the drive member has a lower end portion attached to a lower axis sectional element and an upper end portion attached to an upper axis sectional element. In this case, it is preferable that a plurality of drive members are installed in parallel around the rotating member.
Also, it is preferable that the robot of the present invention comprises: a guide portion for guiding up movement or down movement of the plurality of axis sectional elements driven by the main up-down means and the subordinate up-down means and is more preferable that the guide portion is provided adjacently to the subordinate up-down means.
In the robot of the present invention, the telescopic-drive mechanism for extending/retracting the axis sectional elements is integrated on one side of the up-down axis without being exposed therefrom, the powder dust generated as a result of operation of the telescopic-drive mechanism is prevented from flying to all directions in the clean room, and simultaneously, the configuration of the robot can be simplified.
In addition, since transfer and installation can be carried out with the robot retracted, space efficiency in transfer is improved and complexity of installation operation is avoided. Correspondingly, a transfer cost and an installation cost are reduced.
Further, according to still another preferred embodiment of the present invention, since the operation axis unit is rotatably provided at the top portion of the up-down axis, the foot area in equipment which the robot occupies becomes substantially as small as a bottom area of the first axis sectional element at the base end, and therefore, the equipment can be easily made compact. Moreover, since the operation axis unit is positioned at the highest position, the work such as the wafer is prevented from being contaminated by the power dust caused by the operation of the operation axis unit.